package cuppics;

import org.junit.Test;

public class Prj28 {

	
	/**
	 * Starting with the number 1 and moving to the right in a clockwise direction a 5 by 5 spiral is formed as follows:

21 22 23 24 25
20  7  8  9 10
19  6  1  2 11
18  5  4  3 12
17 16 15 14 13

It can be verified that the sum of the numbers on the diagonals is 101.

What is the sum of the numbers on the diagonals in a 1001 by 1001 spiral formed in the same way?
	 */
	@Test
	public void test(){
		System.out.println(Calculator.calculate());
	}
	
	
	public static class Calculator{
		
		public static int calculate(){
			
			int lastEnd = 1;
			int sum = 1;
			for( int i = 3; i <= 1001; i = i + 2 ){
				int [] fourAngle = getFourAngle( lastEnd + i - 1, i - 1 );
				sum += fourAngle[0];
				sum += fourAngle[1];
				sum += fourAngle[2];
				sum += fourAngle[3];
				

				System.out.print(fourAngle[0] + "," + fourAngle[1] + "," + fourAngle[2] + "," + fourAngle[3]);

				System.out.println();
				
				lastEnd = fourAngle[3];
			}
			
			
			return sum;
		}

		private static int[] getFourAngle(int startPt, int interval) {
			
			return new int[]{ startPt , startPt + interval, startPt + 2 * interval , startPt + 3 * interval};
		}
		
	}
	
}
